A barcode can be nominated as an object for identifying goods. The barcode is printed on goods directly by flexography (a printing method using a relief plate made of rubber or flexible synthetic resin), offset printing, gravure printing, and the like; or printed on a label first, before being attached to goods. By using a barcode, data of a barcode (price or name of merchandise) can be read by an optical reading device also called a barcode reader. According to the data, management of the sales volume, stocks, and distribution can be conducted. However, there are problems of a barcode in terms of information and function, for example, a number of digits is small and security is not ensured.
In recent years, there has been an attempt to conduct management of goods, streamlining of distribution, and management of information of merchandise by mounting a semiconductor device which can send and receive data wirelessly, typically an item called a wireless chip (also called an ID tag, an IC tag, an IC chip, an RF (Radio Frequency) tag, a wireless tag, an electric tag, or an RFID (Radio Frequency Identification)) on goods instead of using a barcode. However, a wireless chip has an inconvenient aspect that communication with a reader/writer having an antenna is required to know the information in a wireless chip, and the information can not be known without a reader/writer. Also there arise problems of security such as a fear that unauthorized rewriting of the information of a wireless chip may be conducted or a fear of forgery of a wireless chip itself. In addition, there is a problem that the information itself may be lost or may not be read if an IC tag is broken for any reason.